Preparing the GEOGRAPHY for the 2011 Population Census of South Africa

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1 Preparing the GEOGRAPHY for the 2011 Population Census of South Africa Sharthi Laldaparsad Statistics South Africa; Abstract: Statistics South Africa (Stats SA) s Geography Division is currently preparing the 2011 population census geography frame for South Africa. This paper presentation focuses on four key areas. The first is the process to align all census boundaries (collection geographies) to the most recent official administrative boundaries (dissemination geographies) for South Africa. The second is the massive undertaking to create a national dwelling frame for South Africa which also includes the ambitious task of assigning addresses to the almost 50% dwellings, falling mainly in rural and informal areas, that have no addresses. The third is to maintain our place name or locality database, a fundamental component of an address and main dissemination geography. The last is to delineate the census collection boundaries namely the enumeration areas (EA). The paper discusses the methodologies, technologies, progress and challenges so far. Key words and phrases: Geography frame. Census boundaries. Collection geography. Dissemination geography. Administrative boundaries. Dwelling Frame. National address database. Place name. Enumeration areas. South Africa. Statistics South Africa. Introduction The preparation for a population census starts many years before Census Day with the mammoth task of preparing the census geography frame, the foundation for a quality census. The census geography frame consists of the official administrative boundaries of the country, place name (locality) boundaries, small area boundaries (i.e. EAs aggregated to prevent data disclosure, released with limited census data) these making up the key dissemination geographies; then EA boundaries, fieldwork management areas and dwelling locations making up the key collection geographies. This paper focuses on four key areas currently in progress as we prepare for the upcoming census in South Africa, in

2 Alignment to official administrative boundaries Official administrative boundaries for South Africa are maintained by the Municipal Demarcation Board (MDB). The 2011 census geography will align to the latest boundaries as supplied by the MDB. This will ensure that a national geographic standard is maintained from collection to output geography. The map below shows the changes in municipal boundaries from the 2005 to the latest 2011 dataset. Changing administrative boundaries are a challenge for statistical data release. Boundaries were updated for the 2009 national and provincial elections and for the local government elections planned for March Boundary changes are managed well as Stats SA is a member of the MDB s boundary s committee and official boundary releases are well communicated. Creating a National Dwelling Frame The objectives of the geo-referenced Dwelling Frame is to identify (physical address) and locate (geographic coordinate) and describe all structures on the ground. The project includes the continuous maintenance of such a frame that can be used as fundamental statistical framework data for censuses and surveys conducted by ourselves and other role-players in the broader National Statistical System (NSS). In other words, the Dwelling Frame together with the Business Register and the Population Register forms the pillars of quality statistics. The Dwelling Frame started with the main focus on allocating addresses to about 50% of the country s residents that have no addresses - mainly in the former homelands of South Africa. (As shown in the picture below the homestead received numbers from each of the different service providers, even Stats SA during the censuses spray-painted numbers on the wall.) 2

3 The project was piloted in 2002 in the village of Botseleni in the province of Limpopo where dwellings were geo-referenced and addresses were for the first time displayed on homesteads. The project to assign addresses in areas with no addresses is gaining momentum and the target is to complete the entire country by December 2010, so that the address can be used as the main unique physical identifier for the 2011 Census. A mixed methodology is adopted for the collection of data. For urban areas, in cases where address data are available in spatial format, from a variety of sources, a rigorous assessment is done to ensure that it meets quality standards. Urban and urban informal areas are captured using GPS devices, data is sent from the field (all over the country) to head-office in Pretoria via GPRS technology every 30 minutes. A head-office team quality checks the data. The pass rate so far is 99.4%. A 5% sample of points (per EA) is selected at Head-office, sent via GPRS to field supervisors to conduct field quality control. A 100% pass rate on the sample check is currently maintained. For rural areas (farming settlements), depending on the level of access, GPS & GPRS technology or a centralized collection method is deployed. The centralized method involves soliciting data about the farms from farm union representatives by examining aerial or satellite photography. For traditional areas a centralized collection method is undertaken. Data is obtained from the traditional leadership (and others as designated by the leadership) for the village by 3

4 annotating on aerial or satellite photography. Up to date aerial and satellite photography is important for the success of the centralized data collection method. Stats SA therefore makes a substantial investment in photography by collaborating with other Government Departments. This photography is made available freely to all Government Departments for use in Government-wide projects. The pictures below shows dwellings mapped on aerial photography and its associated attributes. About 6.4 million of the estimated 11 million dwellings are mapped (as at 29 June 2009). Continued maintenance of the Dwelling Frame is important. Coordination amongst several roleplayers, like Department of Land Affairs for linkages with the cadastre and availability of aerial 4

5 photography, Department of Provincial & Local Government with similar databases like the valuation roll and local address systems, South African Post Office with physical and postal addresses, and others, will continue for the Frame s sustainable maintenance. Providing addresses to areas with no addresses The process to assign addresses to homesteads in traditional areas has commenced. During the geo-referencing phase, any existing addresses as assigned by different service providers are recorded. These existing addresses are analyzed, if complete and logical, it is accepted. If incomplete or illogical, new addresses are discussed and agreed with the local leadership and the service providers, so that a single address system can be implemented. With addresses now these dwellings can be uniquely identified on the census questionnaire, instead of relying only on head of household name or other non permanent descriptive data. The picture below shows address (number plate) nailed on dwelling. Demarcating the country into Places and Enumeration Areas (EAs) Place names (community level geography) were the main lower level of census data dissemination for census Its completeness is therefore important. For census 2011 the Place name geography will be handled separately as its own geography, unlike for previous censuses were Place names were rolled up from EA boundaries, as a result many Place names were excluded. So for census 2011 Place names will be demarcated first, EAs will be demarcated within Place names, both within the municipal structures. Place names will contain two levels i.e. main-place (e.g. cities, towns, former townships, villages, etc.) and sub-place (e.g. suburbs, sub-village, sections, zones, 5

6 etc.) Source data for Place names are the updates as received from the Dwelling Frame, proclaimed boundaries from metro and local municipalities, private sector datasets, topographical maps, databases as supplied by the South African Names Council and other hard copy atlases. The demarcation of EAs occurs within the administrative structure (Province, District, and Municipality), place name, geography-type and EA-type. Geography-types are classified into 3 categories namely urban, rural and traditional, based on official proclamations. EA-types describe the dominant activity/ land-use within the EA. There are 10 categories namely formal residential, informal residential, traditional residential, farms, small-holdings, commercial, industrial, collective living quarters, parks (parks, recreational areas and state parks) and vacant. EA size is important. It determines the enumerators work load for the stipulated days for census data collection. Due to varying circumstances for each EA-type different size requirements were derived based on factors such as distance, area, estimate time to complete the questionnaire, hours in the day households are available, etc. The wheels have started turning, so far 20% of Place names and 13% of EAs are demarcated (as at 29 June 2009). Conclusion Geography preparations are on track to conduct the Census Pilot in October Place names & EAs for the Pilot are demarcated together with its corresponding dwellings from the Dwelling Frame. Listers/ Enumerators are expected in the first place to return a record for each dwelling as stipulated on the Frame, then to indicate areas of change for the continued maintenance of the Frame. Utilizing a Dwelling Frame will be piloted for the first time for our census-taking a milestone for us. 6